There has recently been a proliferation of recreational vehicles (RV's) on the market, including camping trucks, motor homes, private vans, sport trucks, et cetera each appealing to a particular segment of the public. Such vehicles are used as RV's primarily during the summer months and most of them are restricted to normal road use. Even those vehicles which are capable of off-road use are used primarily as such during the summer months as they are not capable of traversing deep snow. Certain vehicles, typically snowmobiles, are designed strictly for use in snow but they, in turn, are less than effective as normal road vehicles.
In the past there have been many attempts to convert road vehicles to off-road use, most such attempts involving the provision of endless tracks which can be attached to and driven by the vehicle drive wheels. Such attempts are typified by U.S. Pat. Nos. 2,683,608 (Matheson, July 13, 1954); 1,566,085 (Geaudreau, Dec. 15, 1925); 1,238,762 (Hapeman, Sept. 4, 1917); 1,117,139 (Olmstead et al, Nov. 10, 1914); 2,782,076 (Miller, Feb. 19, 1957); 2,556,270 (Groeller, June 12, 1951) and 1,701,212 (Nickerson, Feb. 5,1929). Another interesting attempt at converting a vehicle to off-road use, in fact to marine use, is found in U.S. Pat. No. 2,282,745 (Preston, May 12, 1942). In the Preston patent a floating trailer having retractable road wheels has traction belt means engageable by the vehicle's drive wheels for, in turn, driving a pair of propellors to achieve propulsion when in the water. The vehicle is supported by the trailer platform when the device is in its marine configuration.
All prior art devices as typified by the above-identified U.S. patents have the shortcoming that extensive mechanical changes must be effected before the vehicle is suitable for off-road use and that the loading per square foot of track is so great that performance on snow or other unconsolidated surfaces, such as tundra, is impeded. The Preston device of course is only usable in a marine environment and as such cannot be used on snow or tundra.
There is therefore a need for a device which is simple to operate and economical to produce which can readily transform a road vehicle to an off-road vehicle to extend the effectiveness of the vehicle during winter months and in areas where the vehicle would be otherwise useless.